11-oxabicyclo [4.4.1] undecanes and their preparation



Patented Mar. 13, 1951 UNlTED STATES 1 PATENT OFFICEII-OXABICYCLO[4.4.1]UNDECANES AND THEIR PREPARATION Clement W. Theobald,Wilmington, Del., assignor to E. I. du Pont de Nemours & Company,Wilmington, Del., a corporation of Delaware No Drawing. ApplicationJanuary 7, 1949, Serial No. 69,843

Claims. (Cl. 260-333) I (page 101). Hitherto there has been no knownleast one hydrogen atom attached to each annular carbon atom and notmore than one alkyl radical which is attached to an annular carbon atomwith all the remaining valences of the annular carbon atoms beingsaturated by hydrogen atoms. Thus the new bicyclic ethers of thisinvention correspond in structure to the following formula:

where R is selected from the group consisting of hydrogen and alkylradicals, not more than one R is an alkyl radical and all the remaining-Rs are hydrogen. R is preferably hydrogen or an alkyl radical of from 1to 3 carbon atoms, that is methyl, ethyl or propyl.

It has now been discovered that fi-oxycyclodecanones-l, in which theoxy-substituent is hydroxy or alkoxy, can be successfully subjected tohydrogenolysis to produce good yields of newbi-' cyclic ethers. The6-oxycyclodecanones-1 contain not more than one alkyl radical attachedto an annular carbon atom with all remaining va- 2 lences of the annularcarbon atoms being satisfied by hydrogen atoms. Thesefi-oxycyclodecanones-l correspond in structure to the following formula:

where OR is hydroxy or alkoxy, R is hydrogen or alkyl, and not more thanone R is an alkyl group, with the remaining Rs being hydrogen.

The new bicyclic ethers of this invention are obtained by passing avapor mixture of the 6-hydroxyor G-alkoxycyclodecanone and hydrogen overa noble metal catalyst, e. g., platinum, heated to a temperature of 140to 350 C. The vapor mixture is preferably passed over the noble metalcatalyst continuously at essentially atmospheric pressure. From thereaction mixture the desire bicyclic ether is recovered. A suitableapparatus for effecting the hydrogenolysis of this invention consists ofa U-shaped reactor suspended in a bath of boiling liquid and equippedwith a feed burette, a hydrogen inlet, and a condensing system to removehigh-boiling products from the vapor stream.

In operation, the material to be subjected to hydrogenolysis andhydrogen are fed to one arm of the U-tube which is packed with glasshelices and serves as a preheater section. The heated gas mixture isthen passed over the catalyst bed in the other arm of the U-tube andthen to the condensing system.

A suitable platinum catalyst is prepared by pouring a solution of 10.60grams of chloroplatinic acid in 400 cc. of distilled water over 400 cc.

(lgrams) of nitric acid-extracted, Washed, and dried charcoal of 4-14mesh. This suspension is stirred and the water evaporated by heating ona steam bath with intermittent manual stirring. Before the start ofoperation 50 cc. of this catalyst is placed in the reactor and heated tobetween and 350 C. under a hydrogen flow of 200 l./hr. After 1 hour and20 minutes at the selected temperature the 6-hydroxyor 6-alkoxy-'cyclodecanone is added from a steam-jacketed, constant head additionburette. The examples Whichfollow are submitted to illustrate and'not tolimit this invention.

Example I into the reactor previously described, heated to 155 C. andpacked with 50 cc. of the platinumon-charcoal catalyst, prepared asdescribed, there was added 6-hydroxycyclodecanone-l at a rate between 4and 4,5 grams/hr. for a period of 9 hours, maintaining the hydrogen flowat the rate of 200 l./hr. meanwhile. A total of approximately 40 gramsof 6-hydroxycyclodecanone-l was added during this time. The hydrogenflow was maintained for a period of 1.5 hours after addition of the lastof the G-hydroxycyclodecanone-l. The product collected consisted of alower aqueous layer weighing 5.10 grams and an upper organic layerweighing 21.50 grams. The layers were separated, the aqueous layerextracted with carbon tetrachloride and the combined organic layersdried over anyhdrous sodium sulfate. After removal of the organicsolvent, the residue was distilled. After a small foreshot, a fractionboiling at 70 C./8 mm., n 1,4709, weighing 3.52 grams was collected. Asecond fraction boiling at 86 C./8 mm., freezing point 22.8 C., 71.1.4838 and weighing 9.4 grams was obtained. The analysis and physicalproperties of the first fraction indicated it to be a hydrocarbon.

Anal. calcd for C1oH2o2 C, 85.62; H, 14.37. Found: C, 85.49, 35.32; H,14.39, 14.25.

The material was insoluble and unaffected by concentrated, cold,sulfuric acid and gave an infrared spectrum similar to the spectrum ofan authentic sample of cyclodecane.

The higher boiling fraction was soluble in cold concentrated sulfuricacid with the development of a yellow color, gave no reactions for OH or(3:0 functional groups and analyzed correctly for the compositionC10H18O as follows:

Anal. calcd for CmHmQ: C, 77.87; H, 11.76. Found: C, 77.61, 77.74; H,12.06, 11.98.

The infrared spectrum of this material indicated the complete absence ofcarbonyl or hydroxyl groups and an absorption band ,in the proper regionfor an ether group. ,From its composition, inertness and infraredspectrum, the structure, ll-oxabicyclo[dellundecane has been assigned tothis compound. The yields of the cyclodecane and the1l-oxabicyclo[4.4.1lundecane, calculated on the G-hydroxycyclodecanone-lreacted were 23% and respectively.

Example 11 Operating with the same apparatus and by a similar procedureto the above example, 35.0 grams of 6-methoxycyclodecanone-1 was addedat an average rate of 5.25 grams/hr. The liquid product again consistedof two layers whose combined weight was 29.83 grams. Upon fractionation,a .10 yield of the hydrocarbon and a yield of the cyclic ether wasobtained. The higher boiling material from this run was identical withthe corresponding fraction in the above example as shown by the factthat a mixture of the-two compounds did not exhibit a depression of thefreezing point.

Although the examples have illustrated certain specific conditions ofcatalyst concentration, space velocity, temperature, duration ofreaction, etc., it is to be understood that these may be varied somewhatsince the conditions of each experiment are determined by the particularcompound being reacted, the temperature employed, andother reactionconditions.

In general, the hydrogenolysis is effected at pressures which areessentially atmospheric and temperatures which range from to 350 G.Since satisfactory reaction rates are obtained at temperatures of fromC. to 300 C. this range constitutes the one most useful in actualpractice. If desired pressures which are slightly above or belowatmospheric may be used.

The amount of hydrogen used is at least one mole per mole of 6-hydroxyorB-alkoxycyclodecanone employed. In actual practice, larger amounts ofhydrogen are used to aid in the vaporization of the G-hydroxyor6-alkoxycyclodecanone, to insure complete reaction, and to aid in theremoval of the exothermic heat of reaction. If desired this hydrogen maybe diluted with an inert gas such as nitrogen or carbon dioxide to aidin the dissipation of the heat of reaction.

In practice it is necessary to employ very eificient condensing means torecover the hydrogenolysis product carried over by the excess hydrogen,and also to recirculate the hydrogen through the reactor, in order toinsure complete recovery of these ethers. In the laboratory it isdiincult to attain these conditions, and for this reason the yieldsgiven in the examples are lower than the actual yields under theconditions employed.

Any suitable platinum catalyst may be used, Thus, there may be employedmetallic platinum or any of its compounds such as the oxide, chloride,hydrochloride, etc. either unsupported or supported on such materials ascharcoal, alumina, pumice, kieselguhr, etc. During operation theplatinum compounds are probably reduced to metallic platinum.

Platinum is the preferred catalyst and especially platinum made by thehydrogen reduction of chloroplatinic acid on charcoal as previouslydescribed. Such catalysts appear to have a residual acidity which insome way appears to have an activating effect on the catalyst.

A suitable amount of catalyst is such as to furnish at least.0.001 gramof platinum per gram of compound being processed per hour. Ordinarily,larger amounts of the order of 0.10 gram of platinum per gram ofcompound being processed Der hour, is employed because the advantagesaccruing from the standpoint of speed of reaction offset the addedcatalyst cost.

In place of platinum other noble metal catalysts such as palladium,rhodium and the like may be used.

If desired, the process ma be carried out in the presence of an inertsolyent such as an aliphatic hydrocarbon, acetic acid and other loweraliphatic carboxylic acids, etc. Ordinarily no solvent isemployedbecause the use of such solvent adds to the cost withoutcompensating practical advantages.

The compounds processed according to this invention, to yield the newbicyclicethers of this invention, are the G-hydroxyand the fi alkoxyrcyclodecanones-l. Examples of 'e-alkoii y ilqdecanones-l arefi-methoxycyclodecanone 1, 7 6.- ethoxycyclodecanone-l,fi-isopropyloxycyclodeear none-1, 6-butyroxycyclodecanonee1, ;fi-oetyloxy.- cyclodecanone-l, 6-dodecyloxycyclodecanona1,6.e.oetadecyloxycyclodecanone ;1 13,- methyl firmethoxycyclodecanoneeLand the-,lilge. {1 chain va zcieyc e q i s h vinsi1k stituents containing less than 2 carbonatgrns, such as ox -ethoxy. anfieb trmx cxclod canonesel Offer a antage 19 economy.

ease of preparation, and stability and are therefore the preferred6-alkoxycyclodecanones-1. However, as the hydroxy or alkoxy substituentis removed on hydrogenolysis any 6-alkoxycyclodecanone-l can be employedincluding those having alkoxy substituents containing up to 18 or morecarbon atoms. Alkyl-G-alkoxycyclodecanones-l in which the alkyl radicalcontains from 1 to 3 carbon atoms are preferable to produce alkyl-1 1-oxabicyclo[4.4.1]undecanes. However, 6-alkoxycyclodecanones-1 having analkyl substituent containing up to 18 or more carbon atoms can be used.

The bicyclic ethers of this invention are useful as intermediates forother syntheses, for example, for conversion to glycols, as solvents,plasticizers, and the like.

As many apparently widely different embodiments of this invention may bemade Without departing from the spirit and scope thereof, it is to beunderstood that this invention is not limited to the specificembodiments thereof except as defined in the appended claims.

I claim:

1. A method of preparing an ll-oxabicyclo- [4.4.1]undecane whichcomprises passing a vapor mixture of hydrogen and afi-oxycyclodecanone-1 in which the oxy-substituent is selected from thegroup consisting of hydroxy and alkoxy radicals over a noble metalcatalyst heated to a temperature of 140 to 350 C., said6-oxycyclodecanone-l containing not more than one alkyl radical of 1 to3 carbon atoms attached to an annular carbon atom, all remainingvalences of said annular carbon atoms being satisfied by hydrogen atoms,and said vapor mixture containing at least one mole of hydrogen per moleof 6-oxycyclodecanone-1.

2. A method of preparing an ll-oxabicyclo- [4.4.1]undecane whichcomprises passing a vapor mixture of hydrogen and a 6-oxycyclodecanone-1in which the oxy-substituent is selected from the group consisting ofhydroxy and alkoxy radicals over a platinum catalyst heated to atemperature of 140 to 350 C., said 6-oxycyclodecanone-l containing notmore than one alkyl radical of 1 to 3 carbon atoms attached to anannular carbon atom, all remaining valences of said annular carbon atomsbeing satisfied by hydrogen atoms, and said vapor mixture containing atleast one mole of hydrogen per mole of G-oxycyclodecanone-l.

3. A method of preparing an 11-oxabicyclo- [4.4.1]undecane whichcomprises passing a vapor mixture of hydrogen and a6-hydroxycyclodecanone-l over a platinum catalyst heated to atemperature of 140 to 350 C., said fi-hydroxycyclodecanone-l containingnot more than one alkyl radical of 1 to 3 carbon atoms attached to anannular carbon atom, all remaining valences of said annular carbon atomsbeing satisfied by hydrogen atoms, and said vapor mixture containing atleast one mole of hydrogen per mole of 6-hydroxycyclodecanone-1.

4. A method of preparing an ll-oxabicyclo- [4.4.1lundecane whichcomprises passing a vapor mixture of hydrogen and a6-alkoxycyclodecanone-l over a platinum catalyst heated to a temperatureof to 350 C., said G-alkoxycyclodecanone-l containing not more than onealkyl radical of 1 to 3 carbon atoms attached to an annular carbon atom,all remaining valences of said annular carbon atoms being satisfied byhydrogen atoms, and said vapor mixture containing at least one mole ofhydrogen per mole of 6-alkoxycyclodecanone-1.

5. A method of preparing ll-oxabicyclo- [4.4.1]undecane which comprisespassing a vapor 'mixture of hydrogen and G-hydroxycyclodecanone-l over aplatinum catalyst heated to a temperature of 140 to 350 C., said vapormixture containing at least one mole of hydrogen per mole of6-hydroxycyclodecanone-1.

6. A method of preparing ll-oxabicyolo- [4.4.1]undecane which comprisespassing a vapor mixture of hydrogen and a 6-alkoxycyclodecanone-l over aplatinum catalyst heated to a temperature of 140 to 350 0., allremaining valences of the annular carbon atoms being satisfied byhydrogen atom and said vapor mixture containing at least one mole ofhydrogen per mole of 6-alkoxycyclyodecanone-1.

7. A method of preparing ll-oxabicyclo- [4.4.1lundecane which comprisespassing a vapor mixture of hydrogen and 6-methoxycyclodecanone-l over aplatinum catalyst heated to a temperature of 140 to 350 C., said vapormixture containing at least one mole of hydrogen per mole of6-methoxycyclodecanone-1.

8. An 11-oxabicyclo[4.4.1lundecane containing at least one hydrogen atomattached to each annular carbon atom and not more than one alkyl radicalof 1 to 3 carbon atoms attached to an annular carbon atom, all remainingvalences of said annular carbon atoms being satisfied by hydrogen atoms.

9. An ll-oxabicyclo[4.4.1]undecane containing at least one hydrogen atomattached to each annular carbon atom and one alkyl radical of 1 to 3carbon atoms attached to an annular carbon atom, all remaining valencesof aid annular carbon atoms being satisfied by hydrogen atoms.

10. The chemical compound ll-oxabicyclo- [4.4.1lundecane.

CLEMENT W. THEOBALD.

No references cited.

10. THE CHMICAL COMPOUND 11-OXABICYCLO-(4.4.1)UNDECANE. 